Mine hoist with relockable winding drums

ABSTRACT

A mine hoist includes a shaft with two drums mounted thereon, one of which is turnable with respect to the shaft. An arrangement is provided for adjusting the relative angular positions of the shaft on the two drums. The movable drum is normally connected to the shaft by a friction clutch which is held in engagement by spring pressure and is released by the operation of a fluid pressure cylinder.

United States Patent lnventors Appl. No. Filed Patented Aasignec Priority MINE HOIST WITH RELOCKABLE WINDING DRUMS References Cited UNITED STATES PATENTS Primary Examiner1-1arvey C. Hornsby Assistant Examiner-Merle F. Maffei Attorney.1ennings Bailey, Jr.

ABSTRACT: A mine hoist includes a shaft with two drums mounted thereon, one of which is turnable with respect to the shaft. An arrangement is provided for adjusting the relative angular positions of the shaft on the two drums. The movable drum is normally connected to the shaft by a friction clutch which is held in engagement by spring pressure and is released by the operation ofa fluid pressure cylinder.

2 Claims, 3 Drawing Figs. U.S. Cl 254/185, l88/73.5, 188/170, 192/55 Int. Cl B66d l/26, 866d 1/44, B66d 5/00 Field of Search 254/185; l88/170,73.5;192/55 8 2 l 4 I I PATENTEU SEP1 4197i SHEET 3 [IF 3 INVENTOR E/NAF? EITHUIV JOSEF MAfiCHNE/P BY W K MINE HOIST WITH RELOCKABLE WINDING DRUMS BACKGROUND OF THE INVENTION 1. Field of the Invention In mines with haulage from two or more different levels hoists are often used having two skips. These are suspended in individual cables each wound onto its own winding drum on a common winder in opposite directions so that one skip is in the loading station while the other is simultaneously at the unloading station. For this it is necessary that at least one of the winding drums can be released from a common driving means, usually a shaft connected to a common driving motor.

2. The Prior Art In known mine hoist constructions this connection is in the form of a controllable clutch such as a dog clutch. These types of clutches are not completely satisfactory. When an alteration is to be carried out, the drums must be stationary during the coupling and furthermore an accurate indication of the angular relation between the winding drums is necessary and these must be stopped in an exact relative position in order to allow reengagement of the clutch elements after a separation. Since the skips balance each other, the brakes of the individual drums do not have to be able to hold the torque generated by the wire tension for the hoist to be able to operate reliably. If the drums were to be released from each other with loaded skips, there is a certain risk that the holding torque of the brakes would be insufficient with the result that accurate adjustment cannot be obtained and the reconnection is made more difficult, or the skip cannot be held and falls down to its lowest position, possibly resulting in considerable damage.

In excavators there are sometimes two winding drums on a common driving shaft. In one type, one of the winding drums is fixed to the shaft and the other is rotatable and axially displaceable on the shaft. The rotatable drum can be displaced along the shaft to make contact with a conical friction surface on the other winding drum or on a stationary disc, and in this way be connected to either of these. Both discs may be rotatable and axially displaceable on the shaft between stationary braking discs and a common driving disc attached on the shaft. During the displacement the winding drum can rotate freely on the shaft.

The winding drum in large mine hoist may weight 25-100 tons and cables and skips -50 tons. These weights alone and the torque generated by cables and skips even during the switching mean that the structural principles known from excavators, having axially displaceable winding drums, cannot be used or provide any indication of how the problem should be solved in mine hoists.

SUMMARY OF THE INVENTION The present invention relates to mine hoists having two skips suspended by cables which are wound in opposite directions onto individual winding drums, axially fixed and arranged on a common shaft, at least one of the drums being rotatable about the shaft and connected to it by a detachable connection which makes possible adjustment of the position of the winding drums in relation to each other and locking of the winding drums at the desired angle to each other.

According to the invention the connection is designed as a drum or disc friction clutch which is engaged by spring force and released by at least one lifting cylinder operated by pressure medium. The connection is most favorably designed as a disc clutch having at least one, preferably two friction discs joined to the cable drum and at least one hub firmly attached to the common shaft of the winding drums, said hub supporting clutch units straddling said disc, said units having, on opposite sides of the disc, pads of frictional material, one adjacent each facing side of the disc and axially movable into frictional engagement with said facing sides of the disc, resilient means normally forcing said friction pads into frictional engagement with said disc and a fluid pressure operated piston and cylinder means operable to move said friction pads against said resilient means and away from said clutch disc. The winding drum disc or discs have a limited axial movement and are radially movable. When two connecting discs are present in the winding drum the hub supports at least one clutch disc which projects between the discs of the winding drum so that the number of friction surfaces is doubled. The clutch discs of the drum are annular whereas the clutch discs joined to the hub consist of segments having approximately the same size in circumference as the friction pads on the clutch units. By means of the invention the switchover from one loading level to another is facilitated. The clutch can be connected and the connection of the winding drums takes place at any chosen angle. Only the position of the skip must be indicated. The risk that the winding drums will not be able to be connected together again after being released from each other because a skip cannot be stopped has been completely eliminated. The clutch can be more easily and reliably remote controlled which facilitates remote control and labor-saving automization.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be further described with reference to the accompanying drawings.

FIG. 1 shows a view of a hoist with driving motor and intermediate gear.

FIG. 2 shows on a larger scale the section indicated in FIG. 1 and,

FIG. 3 a side view of the clutch.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawings 1 designates a driving motor, 2 a gear, 3 and 4 two winding drums which are arranged on a common shaft 5 which is supported by three bearings 6. The winding drums are provided with outer braking discs 7 and 8 and with braking units 9 and 10 which, during normal operation of the hoist, are operated simultaneously for engagement and disengagement with the discs. The drum 4 is joined to the shaft 5 while the drum 3, by means of discs 11, hubs 12 and bushings l3 and 14 in the hubs 12 on the shaft 5, respectively, is rotatably arranged about the shaft 5 and thus rotatably arranged in relation to the drum 4. In the winding drum 3 are two annular clutch discs 15 which have a limited axial movement and are radially movable in relation to the drum itself since they rest on a number of rubber bushings 16 on pegs 17 in the annular parts 18 and 19 joined to the drum 3. The axial movement is obtained by sliding on the bushings 16 while the radial movement is obtained due to resilience in the elastic material of the bushings. The radially elastic attachment prevents radial loads of a dangerous magnitude being transferred between the drum 3 and shaft 5 if play exists between the bushings l3 and 14. A hub 20 with a disc 21 is joined to the shaft 5 by means of a key fitting or shrinkage fit 35. The disc 21 supports the clutch units 22 and a number of segment-shaped clutch discs 23 with friction coating, which project in between the clutch discs 15. A spacer 24 having the same thickness as the disc 21 is used to ensure that the units 22 are symmetrically arranged in relation to the clutch discs 23. The clutch units 22, spacer 24 and friction discs 23 are fixed to the disc 21 with bolts 24' and 25. The clutch units are of a type in which friction pads are pressed against a clutch disc with spring force and lifted by an operating cylinder such as shown in Tjernstrom, U.S. Pat. No. 3,1 18,520. Standard units developed for clutch brakes can be used as clutch units, which contributes to reducing the costs of the clutch. A number of units dependent on the magnitude of the torque are placed along the periphery of the disc 21. Pressure medium to lift the friction pads 37 of the clutch units 22 is supplied through the conduit 26, the rotating hydraulic connection 27, channels 28 and 29 in the shaft 5, conduit 30 and distributing pieces 31 and conduits 32 and 33.-

The clutch operates in the following way: In normal operation the pressure in the operating conduits is equal to atmospheric pressure and the friction pads of the clutch units are pressed by compression springs against the clutch discs in the drum 3 and these discs are pressed against the intermediate friction discs 23. The absence of overpressure in the operating conduit for most of the operating time means that the rotating hydraulic sealing arrangements may be of simple design and, in spite of this, have a very long life. Before the switchover the skip which is suspended from the winding drum 3 is moved to the unloading station, after which pressure medium is supplied to the clutch units 22 so that their friction pads are lifted and the drum 3 is released from the shaft 5. The braking units of the winding drum are now lifted while the braking units of the winding drum 3 remain in position. By starting the driving motor in one or the other direction the skip suspended from the winding drum 4 can be raised or lowered to the desired stopping level, after which the brakes l0 and the clutch in the winding drum 3 are again connected Haulage can now take place from this new stopping level. The hoist is suitably provided with blocking means which prevent the brakes 9 and the connection in the drum 3 from being released simultaneously. Furthermore, the hoist is provided with safety means which automatically connect the clutch if one of the winding drums should reach an impermissible speed during the switchover. The clutch thus serves as an extra safety brake for both the drums during the switchover.

lclaim:

1. Mine hoist comprising a shaft, two individual winding drums, axially fixed on said shaft, at least one of the drums being rotatable about the shaft, detachable connection means between the rotatable drum and the shaft for permitting adjustment of the position of the winding drums in relation to each other and locking of the winding drums at the desired angle to each other, said connection means comprising a friction clutch which is engaged by spring force and at least one lifting cylinder means operated by pressure medium connected to the clutch for releasing it, said clutch being a disc clutch having at least one friction disc joined to thewinding drum for rotation therewith and at least one hub fixedly attached to the shaft of the winding drums, a pair of clutch units supported on said hub and straddling said disc, said units having, on opposite sides of the disc, pads of frictional material, one adjacent each opposite side of the disc and axially movable into frictional engagement with said opposite sides of the disc, resilient means normally forcing said friction pads into frictional engagement with said disc and said cylinder means comprising a fluid pressure operated piston and cylinder operable to move said friction pads against said resilient means and away from said clutch disc, said friction disc comprises two connecting discs mounted for limited axial and radial movement in the winding drum and a substantially segmentshaped clutch part mounted on said hub and extending between the connecting discs for engagement therewith.

2. Mine hoist according to claim 1, having spring means suspending the clutch disc in the movable drum so as to allow limited movement of the disc in relation to the drum. 

1. Mine hoist comprising a shaft, two individual winding drums, axially fixed on said shaft, at least one of the drums being rotatable about the shaft, detachable connection means between the rotatable drum and the shaft for permitting adjustment of the position of the winding drums in relation to each other and locking of the winding drums at the desired angle to each other, said connection means comprising a friction clutch which is engaged by spring force and at least one lifting cylinder means operated by pressure medium connected to the clutch for releasing it, said clutch being a disc clutch having at least one friction disc joined to the winding drum for rotation therewith and at least one hub fixedly attached to the shaft of the winding drums, a pair of clutch units supported on said hub and straddling said disc, said units having, on opposite sides of the disc, pads of frictional material, one adjacent each opposite side of the disc and axially movable into frictional engagement with said opposite sides of the disc, resilient means normally forcing said friction pads into frictional engagement with said disc and said cylinder means comprising a fluid pressure operated piston and cylinder operable to move said friction pads against said resilient means and away from said clutch disc, said friction disc comprises two connecting discs mounted for limited axial and radial movement in the winding drum and a substantially segment-shaped clutch part mounted on said hub and extending between the connecting discs for engagement therewith.
 2. Mine hoist according to claim 1, having spring means suspending the clutch disc in the movable drum so as to allow limited movement of the disc in relation to the drum. 